Power supply circuits often supply an output current that flows through an inductor of the power supply. Typically, it is desirable to maintain the output current of such a power supply circuit below an Over Current Protection (OCP) level. To maintain the output current below the OCP level, the output current of the power supply must be sensed. One technique to sense the output current is to place a sense resistor in a path of the output current. However, this is usually undesirable due to the power dissipated through the sense resistor.
To avoid placing a resistor in the path of the output current, Direct Current Resistance (DCR) sensing techniques are often employed. Conventional DCR sensing circuits include a resistor and a capacitor in parallel with the inductor of the power supply. The voltage across the capacitor is sensed during operation of the power supply. The output current can be determined from the sensed voltage across the capacitor. However, to accurately determine the output current, DCR sensing techniques require knowing a resistance of the inductor. The resistance of the inductor is often referred to as a parasitic resistance or a DC resistance of the inductor. During operation of the power supply, the temperature of the inductor will increase. Because the resistance of a conductor varies proportionally with temperature, the DC resistance of the inductor will also increase as the temperature of the inductor increases. Consequently, variations in temperature can result in inaccurate output current sensing when conventional DCR sensing techniques are employed. A solution that overcomes these challenges is desired.